Modern telecommunications switching systems generally comprise a switching network and a controller which operates under the control of a program and data stored in memory. This program and its associated data are referred to herein as the generic program. A given generic program provides numerous services and features for the switching system and its subscribers. An objective in the design of telecommunications switching equipment is to provide a system which continuously provides services and features to its subscribers. A significant contribution to attaining that objective is the provision of duplicated equipment such as controllers. With duplicated controllers, one is used to control the switching network and if it fails the other can be substituted for the first to provide continuing service.
From time to time, it may be desirable to change a generic program to add or delete features or to provide existing features in an improved manner. Thus, a new generic program is written which will achieve the desired result when executed by the controllers. Typically, when the generic program is updated, the old generic program is replaced with the new generic program in the one of the duplicated controllers not controlling the switching network. Then, the roles of controllers are switched so that the controller executing the new generic program controls the network. The new generic can then be stored in the non-controlling controller which will be available as a substitute.
Since the generic program is in control of the switching network, faults in the program can substantially affect the quality of service provided to subscribers. Accordingly, new generic programs are tested as exhaustively as practical in a laboratory environment before being used in a switching office in the field. Some faults, however, may remain hidden from developers in the relatively protected environment of the laboratory. Additional faults may be caused by the data which is specific to an individual office and cannot be tested in the laboratory. Such faults may severely affect call processing when a switching office is switched from an old generic program to a new one. Heretofore no effective method has been employed to discover faults in a new generic program under actual field conditions before switching from an old generic program to a new one.
It is an object of the present invention to provide an arrangement in which a first of a pair of duplicated controllers is used to test the operation of the second controller after a new generic program has been stored in the second controller. Operation in this manner provides assurances that the second controller and the new generic program will be able to control the network when the second controller is substituted for the first. By design, the test of the second controller by the first does not negatively impact call processing in the switching network.